Add all dart:html tests from the sdk to test/codegen.

test/codegen/lib/html/geolocation_test.dart

+ // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library geolocation_test;
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+import 'dart:html';
+
+main() {
+  useHtmlConfiguration();
+
+  // Actual tests require browser interaction. This just makes sure the API
+  // is present.
+  test('is not null', () {
+    expect(window.navigator.geolocation, isNotNull);
+  });
+}